Blue dot on screen & warranty void because of modified status

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http://forum.xda-developers.com – HI on my note2 one blue dot is visible from last week. we can only see this on black background. i thought of giving this for warranty service. The problem is on my download mode it's showing "official" bot on about->status menu it's showing modified. how to made is phone as official for submitting for warranty ? before it was rooted. now i changed. The steps i followed to set back to official is: 1. removed flash counter by using "Triangle away". 2. flash official firmware downloaded by using FUS down loader please help to solve this Regards (HowTos)